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	<title>求出1-1/2+1/3-1/4…..1/100的和</title>
	<script>
		/*
			求出1-1/2+1/3-1/4…..1/100的和
			分析：1/1 - 1/2 + 1/3 - 1/4 ... - 1/100
		*/
	
		var sum = 0;
		for(var i=1;i<=100;i++){
			if(i%2===0){
				sum -= 1/i;
			}else{
				sum += 1/i;
			}
		}
		console.log(sum);
	</script>
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